Superhydrophobic Graphene/Nafion\nNanohybrid Films\nwith Hierarchical Roughness

Abstract

The micro- and macroscopic structures of functional films\nstrongly\ninfluence the critical properties, such as superhydrophobicity, which\nexhibits super water repellency with a water contact angle (CA) larger\nthan 150° for self-cleaning and antimicrobial surfaces. However,\nit is difficult to achieve the structural hierarchy of two-dimensional\ngraphene for superhydrophobicity. Herein, we report the fabrication\nof superhydrophobic graphene/Nafion nanohybrid films by controlling\nthe structures with respect to the chemical composition from an interpenetrating\nnetworked and compactly interlocked structure (surface area of 9.56\nm² g^–1) to the hierarchical petal-like,\nporous structure (surface area of 413.46 m² g^–1). The superhydrophobicity of hybrid thin films with a CA of ∼161°\nwas derived from the petal-like structure with hierarchical roughness,\nwhere microscale roughness\nwas produced in the lateral direction of hybrid sheets while nanoscopic\nroughness was created on the edges of hybrid sheets. Furthermore,\nthe wettability and optical and electrical properties of hybrid thin\nfilms can be controlled by manipulating the micro- and macroscale\nstructures through the composition-dependent structural changes.